whiplike appendages that extend from surface of many eukaryotic cells
Cilia= many appendages; flagella= one or two appendages
Both function as ways to move liquid past the cell
Both are made of a cylinder of 9 filaments made up of the following: a complete microtubule, a partial microtubule and a protein bridge made of dynein that connects the two. 1 set of microtubules runs up the middle of the cylinder. Everything is covered by a plasma membrane.
cilia
Current research is being done at UMass Medical School
Led by Professor George Witman, Ph. D
exploring possibility that stationary, non-motile cilia act as sensory antenna
most of the work centers around the outer dynein arm
attempting to link lack of dynein arm formation to diseases in eye, kidney and other body parts
Bibliography, Carrie Schlupp users.rcn.com
Cilia and flagella are external protrusions from many types of eukaryotic cells.
If there are many, they are known as cilia
If there is only one, they are flagella. (Flagella are also longer than cilia, but they are otherwise similar)
They are made up of microtubules
Cilia and flagella move liquids over the surface of cells
For single cells (like sperm) this enables the cell to swim
For anchored cells (like epithelial cells lining mammalian air passages), this provides the cells with the ability to move liquid over the surface
Both cilia and flagella have:
A cylindrical array of 9 filaments with a complete microtubule extending into the tip of the cilium
A partial microtubule that doesn’t extend as far into the tip
Two microtubules can join to form one doublet in the cilia or flagella
Cross-bridges of the protein dynein that extend from the complete microtubule of one filament to the partial microtubule of the bordering filament
The dynein arms have ATPase activity. With ATP, the dynein arms enable the tubules to slide against one another so the cilia can bend. This forms a dynein bridge. The dynein bridges are regulated so the sliding can lead to synchronized bending.
A pair of single microtubules running up through the center of the bundle produces the “9+2” arrangement. Motile “9+2” cilia are only found on certain cells in a vertebrate body (ex. Epithelia lining the airways).
Almost every vertebrate cell has had a primary cilium. The primary cilium grows out of the older of the two centrioles that the cell received post-mitosis. The primary cilium does not beat because it does not have the central pair of microtubules, it is “9+0”
The entire assembly of cilia or flagella is covered in a membrane that is an extension of the plasma membrane.
All cilia and flagella grow from and are attached to a basal body in the cytoplasm. Basal bodies are identical to centrioles, and are produced by them.
Jinghua Hu, PhD, at the Mayo Clinic, is currently doing research on cilia.
The long-term goal of his research is to understand how cilia form and function, and to relate these findings to human cilia diseases
The results could provide insight into the molecular basis of PKD and could broaden the understanding of how cilia develop and function in normal and pathological states
Bibliography, Carrie Schlupp
users.rcn.com
Cilia and flagella are external protrusions from many types of eukaryotic cells.
Cilia and flagella move liquids over the surface of cells
Both cilia and flagella have:
The entire assembly of cilia or flagella is covered in a membrane that is an extension of the plasma membrane.
All cilia and flagella grow from and are attached to a basal body in the cytoplasm. Basal bodies are identical to centrioles, and are produced by them.
Jinghua Hu, PhD, at the Mayo Clinic, is currently doing research on cilia.